**5. Insecticide application methods and associated malpractices**

#### **5.1 Application methods**

The mode of application of insecticides is very important for optimizing their functions especially as less than 1% of these applied insecticides get to their target organisms [16, 17]. The over-reliance on chemical pesticides in combating pests throughout the world cannot be emphasized, yet it remains the most efficient, cheap and most accessible control mechanism in controlling pests [18]. Danquah et al. [19] reports cases of organochlorine insecticides residues in Cameroon, Ghana and India within vegetable cultivation, water resources and soil sediments which results largely due to application malpractices.


#### **Table 3.**

*List of highly hazardous insecticides registered in Cameroon.*

#### *5.1.1 Current insecticide application methods widely used in Cameroon*

The desired results of any insecticides can be achieved based on the appropriate methods used and also respecting the time factor. Methods of application varies depending on the nature of the insecticide, their formulation, the soil characteristics, the pests and the availability of clean water [20]. The applications of insecticides is basically for seed treatment, soil treatment or foliar treatment. Insecticides come either in solid, liquid or powder forms, and it is these forms that dictate the methods and appliances used.

#### *5.1.1.1 Sprayers, broomsticks and leaves*

Numerous studies show that in Cameroon and Africa, more than 70% of farmers use sprayers which ranges from knapsack, to motorized knapsack sprayers and others in applying pesticides [19, 21, 22]. It is the most widely used method in the application of insecticides that comes in both powder and liquid forms requiring mixing with water before usage.

As observed with most small scale farmers, the mixing of the insecticides with water is carried out with plastic buckets ranging from 10 to 15 liters while others use their knapsacks, fetching water from nearby streams and using teaspoons, table-spoons or corks of bottles as their measuring units. These are all incorrect estimation measures that lead to either over-dosage or under-dosage of insecticides.

As reported by Christos et al. [22] some resource-poor farmers often improvise by using brooms, mesh and leaves on a wooden short stick in sprinkling pesticides mixed in buckets (**Figure 5**).

#### *5.1.1.2 Dusting*

This is the application of powder insecticides without diluting in water, usually using a duster [22]. In Cameroon very few farmers actually know and use dusters in the application of insecticides. From observation and sampling a handful of tomatoes farmers around Buea, just one in ten farmers know about the dusting techniques and also these few could not afford the duster. These farmers improvise by

*Insecticide Use and Application in Cameroon DOI: http://dx.doi.org/10.5772/intechopen.102634*

#### **Figure 5.**

*Using manual knapsack sprayer on sweet potatoes and fuel-powered sprayer on maize at Ekona, South West Region, Cameroon.*

mixing these insecticides with water and spray. Some farmers apply these powder insecticides with hands upon wearing gloves, without any protective equipment especially for their nostrils and mouth. This practice leads to either over-dosing or under-dosing of plants often resulting in environmental contamination and pollution. Also, farmers have been reported using their bare hands to mix wood ash and terbufos and thereafter apply the mixture on leaves of maize and vegetables such as African nightshade (*Solanum* spp).

#### *5.1.1.3 Granular application*

These are insecticides designed in the forms of solid granules which are made to last longer with the gradual release of the active ingredients slowly upon contact with the soil or roots of plants. In Cameroon more than 70% of the farmers interviewed apply granular pesticides with their hands without any protective, with some using empty tomato tins in spreading them upon the soil.

Most often, these tomato tins serve as their measuring instrument, and depending on the plants, some apply a tin per plantain or banana but for smaller plants like tomatoes, they use a tin for 5–10 plants.

#### **5.2 Malpractices linked to the application methods**

#### *5.2.1 Inappropriate application appliances*

Besides using sprayers, sprinklers and dusters, using of broomsticks and bundles of leaves and brushes attached to sticks and dipping in a bucket of mixed insecticides is the usual practice in Cameroon and in most other African countries [19, 21]. This leads to ineffective application of insecticides resulting in wastage and environmental pollution.

#### *5.2.2 Application without personal protective equipment (PPE)*

In Cameroon, applying pesticides without all the required PPEs is a common practice by a majority of small-scale farmers especially as no monitoring mechanism is in place to enforce usage of PPEs. In a studies conducted in Buea by Christos et al. [21] about 76.4% tomatoes farmer use inappropriate or no PPEs during the application of insecticides, while Asongwe et al. [23] shows that 95% of farmers in Bamenda Municipality do not protect themselves during pesticide applications. Rugalema and Mnyone [18] reported scenarios of insecticides sprinkling at homes with the hands.

#### *5.2.3 Incorrect measurement and different mixtures*

Farmers in Cameroon use teaspoons, corks of beer bottles, or corks of containers, together with empty liters as their measuring units for insecticides. Using these listed items as their measuring units most often results in inappropriate measurement of pesticides that automatically results in environmental pollution and possible the contamination of farmers themselves.

Usually water is fetched in any nearby stream or river irrespective of the source or quality and more recently farmers have dug wells where they fetch water for watering their crops especially during the dry seasons with the same buckets used in mixing the insecticide.

Different concentration of different insecticides with varying active ingredients are usually mixed and used in managing insecticides, especially when the pests affecting the plants is unknown. According to Tarla et al. [24], during the rainy seasons farmers in Foumbot apply pesticides as often as twice a week and when the rains are at their peak, their fields are treated thrice a weak. These frequency of treatment overloads the environment and compromises on the quality of the plant with residues.

#### **5.3 Factors affecting Insecticides malpractices**

It is without doubts that pesticides have greatly increased crop productivity and simultaneously contaminated and polluted our soils and water resources, and also affecting our health. The technology used for their application remains hugely remote and archaic in most parts of Africa, particularly Cameroon, and it is the cost for the massive wastage and unnecessary environmental pollution. Some of the main factors affecting insecticides application malpractices include;

#### *5.3.1 Knowledge of farmers*

Many of the malpractices surrounding the safe usage and handling of pesticides is due to the fact that a majority of farmers including vendors have not had any

#### *Insecticide Use and Application in Cameroon DOI: http://dx.doi.org/10.5772/intechopen.102634*

formal training or technical support on the judicious use and safe handling of pesticides; Sonchieu and Blandine et al. [25, 26] pointed out that educational levels is the factor affecting knowledge, attitude and overall practices about pesticides usage.
